1. Field of the Invention
The present invention relates to fuel tank equipment for a vehicle which comprises a filter that is attached to the front end of a fuel suction pump to filter off impurities contained in a liquid fuel.
2. Discussion of the Background
A fuel tank which is mounted in a vehicle is charged with liquid fuel to be sucked from the tank and supplied to an engine by means of a fuel suction pump. The liquid fuel charged in a fuel tank is likely to contain impurities such as dust. Accordingly, it is necessary to take some measures to remove such impurities from fuel to be supplied to an engine.
FIG. 6 shows one example of a centrifugal force-proof vessel in a conventional fuel tank for a vehicle.
When an automobile takes a turn, fuel contained in a fuel tank 51 is biased by the action of centrifugal force, and consequently, suctional action of a suction pump on the fuel is likely to undergo an adverse effect. To avoid this, the centrifugal force-proof vessel 50 is provided as a subsidiary tank so that the fuel is reliably sucked even under centrifugal force.
The centrifugal force-proof vessel 50 comprises a centrifugal force-proof vessel body 52, a pump bracket 53, a fuel suction pump 54 disposed in the pump bracket 53, a filter 56 attached to an inlet port of a bottom plate (not shown) of the pump 54, and return pipe 57.
The fuel which has been caused to flow from the fuel tank 51 into the centrifugal force-proof vessel body 52 is sucked through the filter 56 by means of the fuel suction pump 54, and then supplied to an engine (not shown). Through engine operation, the remaining fuel is allowed to return through the return pipe 57 to the centrifugal force-proof vessel body 52.
The filter 56 comprises a shape retaining frame 59 made of a resin and having a box-like skeleton comprised of beams 58, a filter fabric 60 formed as a closed bag encapsulating the frame 59, and a suction pipe 61 one end of which is inserted into the filter 59 and attached to an upper wall 59a of the frame and the other end of which is connected to the inlet port of the pump 54 outside the filter fabric 60.
In the filter 56 of the conventional fuel tank for a vehicle, however, when the suction pipe 61 is attached to the pump 54, the other end of the suction pipe 61 is press-fitted into the fuel inlet port formed in the bottom plate of the pump 54, and then sealing is effected, followed by fastening by means of a push nut to prevent the other end of the suction pipe 61 from coming off. Consequently, there are problems in that many parts and manufacturing steps lead to an increased cost, and that satisfactory sealing properties at the fit portion can not be attained so that suction efficiency of the pump 54 is impaired.
Further, in the filter 56, the suction pipe 61 is unified with the filter fabric 60 during its molding in such a manner that the suction pipe 61 is inserted into the insertion opening 62 of the filter fabric 60 and yet the peripheral portion 60a of an insertion opening 62 is inserted into a flange 61a, to unify the suction pipe 61 with filter fabric 60. On this account, it is necessary for molding the suction pipe 61 to place the filter fabric 60 into a mold, leading to poor manageability and productivity. Further, such a mold has an enlarged size and tends to be complicated, leading to a high production cost.
Moreover, in the filter 56, no structural measure is taken to avoid abutment of the suction opening 61A of the suction pipe 61 upon the filter fabric 60 which occurs when the the upper wall 59a of the 59 is forced to move downwardly together with the suction pipe 61 due to deflection of the frame 59 caused by jolt of a vehicle or the like, as shown by the phantom line. Accordingly, when the opening 61A abuts upon the filter fabric 60, suction of a fuel is retarded, thereby impairing suction efficiency of the pump 54.